This project was the first PV power plant in Austria realized through a shareholder programme. In 1995 a PV system with a capacity of 10.4kWp was installed on the roof of utility Feistritzwerke-Steweag. The system was
financed by 68 shareholders and the company Feistritzwerke GmbH, which also coordinated the shareholder programme. This project made it possible for environmentally engaged people to own a share of a PV power plant. The project objectives were:
• to replace fossil energy sources by renewable energies;
• to reduce greenhouse gases: with this project 1.5 tonnes CO2 a year can be avoided;
• to demonstrate a PV power plant;
• to encourage the general implementation of PV systems.
The costs were kept as low as possible through careful selection of components, appropriate sizing of PV systems and the use of existing infrastructure and know-how. Hence the prices was kept to €7000/kWp, whereas standard system costs at that time were €9500 to €13,000/kWp. This project showed that big systems could be installed at a favourable price if suitable conditions are available.
At the beginning, sales of share certificates were slow. The project manager put a lot of effort
into this area with a high advertising effort. This led to greater interest in participation by the local population. About 2500 people obtained information about photovoltaics. In the end 68 people bought shares, which financed 80 per cent of the costs, with the remaining 20 per cent financed by the utility.
The solar tree — the new symbol of Gleisdorf — was built in 1998 with a capacity of 7kWp and was connected to the public electricity grid. It stands in the ‘solar street’ which is a 3.5km-long street section, where about 80 objects are powered by photovoltaics, including a public solar clock, advertising boards and street lights. Solar cells have also been used for art and the solar tree is one of these examples. It is 17.3m high and consists of a 12,700kg solid steel sculpture in the form of a tree with five branches holding 140 solar panels.
The tree generates approximately 6650kWh of electricity annually, which can supply about 70 city streetlights in the centre of Gleisdorf. But the solar tree is not only an artistic and technological object that produces electricity. It also underlines the future ideologies in terms of
Street light in the solar street
Source: © Feistritzwerke-Steweag GmbH
energy of Gleisdorf. Furthermore it promotes energy awareness to the people. In this respect the solar tree connects the elements of art, solar technology, and city organization and planning together in one project.
Most of the PV systems in the solar street have been financed by the utility Feistritzwerke, which partly belongs to the city municipality. Hence the projects of the solar street can also be called a city initiative.
The PV power plant and the solar tree were the first steps towards PV application and renewable energies in Gleisdorf. In the following years more PV plants and solar thermal applications were realized. Most of the PV systems are grid- connected systems. Only a few PV systems like road signs, billboards and other demonstration objects are operated off grid.
The largest photovoltaic system in the solar street is a fagade-integrated system with a capacity of 10kWp. The electricity demands of this building can be covered by its PV system.
The headquarters ofAEE (working group for renewable energies) is also another interesting example of a passive solar house with a solar thermal system and a photovoltaic system placed on the roof.